The use of aqueous solutions of neutralized hydroxylamine salts to hydroxamate water-soluble vinyl polymers is well known, see U.S. Pat. Nos. 4,902,751; 4,587,306. The resultant polymers are known to be useful in the reduction of suspended solids in Bayer process streams, see U.S. Pat. No. 4,767,540. These hydroxamated polymers have been prepared by reacting the aqueous hydroxylamine salt solution with an aqueous solution of the polymer to be hydroxamated. Other patents teaching the hydroxamation of amide polymers include U.K. 2,171,127; U.S. Pat. Nos. 3,345,344; 4,480,067; 4,532,046 and 4,536,296.
Reactions which are conducted where the polymer to be reacted is in the form of a water-in-oil emulsion have become increasingly popular due to the fact that the reaction proceeds more readily. The reactants with which the emulsified polymer is to be reacted have been added thereto in many different forms i.e. as solids, as aqueous solutions and as emulsions.
U.S. Pat. Nos. 4,090,992 and 4,151,140 both teach processes wherein a polymer in emulsion form is chemically modified by reacting it with an emulsion of a reactant. Thus, polyacrylamide in emulsion form is hydrolyzed using a sodium hydroxide emulsion according to the teachings of Volk etal in the '140 patent whereas Scanley in the '992 patent teaches the hydrolysis, dialkylaminomethylation and sulfomethylation of amide polymer groups as well as the Hoffman reaction with chlorine or bromine and a base and the exchange of amide nitrogen for the nitrogen of N,N-diemthylaminopropylamine, all in emulsion form. While these references teach some emulsifiers which are useful in the present process, the '992 emulsifiers, because of their low HLB, fail to function satisfactorily in the instant process. Neither reference recognizes the critical HLB limitations of the present invention.
Thus, if water-in-oil emulsions of high molecular weight hydroxamated polymers and high solids content could be more advantageously produced, a problem prevalent in the art would be overcome.